(a) Technical Field
The present invention relates to an apparatus and a method for monitoring a component breakdown of a battery system. More particularly, the present invention relates to an apparatus and a method for monitoring a component breakdown of a battery system to more accurately determine whether a cooling fan that cools the battery of an environment-friendly vehicle or a part related to the cooling fan breaks down.
(b) Background Art
A motor that operates as a power source is mounted within environment-friendly vehicles such as a hybrid electric vehicle, an electric vehicle, a fuel cell vehicle, and a battery module that includes a high-voltage battery, that is, a driving power source of the motor and a high-voltage relay for blocking or supplying electric power is mounted within the vehicle.
A battery cooling system that prevents overheating of a battery and a motor cooling system that cools a motor using a coolant to prevent overheating of the motor are essentially mounted within the environment-friendly vehicle. The battery cooling system in an environment-friendly vehicle is used to cool the battery to a predetermined temperature to maintain an optimum performance.
Thereto, a cooling fan motor (hereinafter, referred to as a cooling fan) that radiates heat generated by a battery and a battery management system (BMS) responsible for an overall control such as control of charging and discharging and a temperature of a battery module, including control of an operation and a stage of the cooling fan are mounted to the battery cooling system used in the environment-friendly vehicle. However, when a temperature of a component such as a battery rises due to a breakdown of the cooling fan, a performance of the battery deteriorates and a lifespan of the battery decreases, resulting in restriction or loss of a function of the environment-friendly vehicle. Thus, a breakdown detecting logic for a cooling fan is applied to a battery management system.
In particular, an example of a conventional method related to detection of a breakdown of a cooling fan will be described with reference to FIG. 1. First, when a temperature of a battery rises to a predetermined temperature or greater, the battery management system orders an operation command to the cooling fan. Next, the cooling fan is operated according to a stage commanded by the battery management system, and a current operation situation is transmitted to the battery management system as a pulse width modulation (PWM) signal. In other words, the battery management system determines an operation state of the cooling fan using the PWM signal received from a cooling fan controller.
Then, when the battery management system fails to receive a PWM signal that represents an operation stage of the cooling fan and a feedback signal of the cooling fan from the cooling fan controller, the BMS determines that the cooling fan has failed (e.g., failure or breakdown has occurred). When the breakdown is determined to be due to no receipt of a PWM signal despite a current temperature of the battery being maintained at a reference value or lower, the cooling fan may be replaced, which increases costs due to a wrong determination and causes an operator to visit a repair center due to the same kind of breakdown.
As another exemplary method for solving the problems, a method has been developed in the related art of detecting a breakdown of a cooling fan motor of a battery cooling system, the method including: driving and stopping a cooling fan motor; measuring a voltage across the cooling fan motor after a predetermined time period elapses; and determining that the cooling fan motor is in a normal state when the voltage across the cooling fan motor is greater than a threshold value, and determining that the cooling fan motor fails when the voltage across the cooling fan motor is less than the threshold value.
However, as a breakdown of the cooling fan motor is determined by measuring only a voltage of the cooling fan motor without considering a current temperature of the battery, an error may be generated in determining a breakdown of the cooling fan motor. In other words, since it may be determined that the cooling fan motor is normally operated (e.g., operating without failure) and another component related to the cooling fan motor fails when a current temperature of the battery is maintained at a reference value or lower, whether the cooling fan motor fails may not be accurately determined by the conventional method of measuring a voltage of the cooling fan motor.